Method for blocking outflow of petroleum or the like due to damage to subsea petroleum well stell pipe or the like

ABSTRACT

The present invention relates to blocking a flow of crude oil or natural gas from a steel pipe for extracting the oil or the like that has been installed in the sea when the steel pipe is broken. When damage occurs to a steel pipe  4  for petroleum or natural gas well that has been installed in the sea, in order to send magnetic particles  21  or the like into the seafloor through an carrying pipe  6  that has been installed and suspended inside the steel pipe  4,  the outflow of petroleum or the like coming from a lower portion of the carrying pipe  6  is blocked by a gate valve  20  provided at a lower portion of a feeding equipment  12  for feeding magnetic particles or the like attached to an upper opening  7  of the carrying pipe  6.  After that, pressurized water is injected into a housing  14  accommodating magnetic particles or the like of the feeding equipment  12  to sweep the magnetic particles  21  or the like in the housing  14  into the carrying pipe  6  and drop the magnetic particles  21  or the like to the lower end of the carrying pipe  6.  The magnetic particles  21  or the like are magnetically adhered to an inner surface of the steel pipe  4  so that the magnetic particles  21  or the like form a mass, suppressing the outflow of petroleum or natural gas. As a result, mortar or concrete  27  can be injected to block the outflow of petroleum or the like.

TECHNICAL FIELD

The present invention blocks a flow of crude oil or natural gas from asteel pipe for extracting the oil or the like that has been installed inthe sea when the steel pipe is broken.

BACKGROUND ART

As a method to, when oil flows out from a hole caused by damage to asubsea petroleum well steel pipe, block the hole, inserting a carryingpipe from the hole and injecting concrete is conceivable. However, evenif this method is carried out, it is not possible to cure concretebecause the outflow pressure of oil pushes back the concrete and theconcrete is dispersed in the seawater.

Accordingly, the following method may be used as an alternative. A steelpipe is buried near the place where a petroleum well steel pipe has beenburied in the seafloor. Then, the steel pipe is connected to the sidewall of the damaged steel pipe in the place where it has been buried inthe seafloor. Then, a barrier material is charged through the steel pipeso as to suppress the outflow of oil. After that, concrete is injected.This method, however, requires troublesome large-scale work, and it istherefore difficult to complete in a short time.

SUMMARY OF INVENTION [Technical Problem]

Mere insertion of a carrying pipe into a hole caused by damage to asubsea petroleum well steel pipe results in, even if concrete isinjected, the concrete being pushed back by the outflow pressure of oil.Accordingly, an object of the present invention is to provide a methodwith which the outflow of crude oil is suppressed prior to injection ofconcrete.

[Method of Solving the Problem]

When damage occurs to a steel pipe 4 for petroleum or natural gas wellthat has been installed in the sea, magnetic particles 21 or the likeare sent deeply into the seafloor through a carrying pipe 6 that hasbeen installed and suspended inside the steel pipe 4. To implement this,the outflow of petroleum or the like coming from a lower portion of thecarrying pipe 6 is blocked by a gate valve 20 provided at a lowerportion of a feeding equipment 12 for feeding magnetic particles or thelike attached to an upper opening 7 of the carrying pipe 6. After that,a switching valve 19 provided at an upper portion of the equipment andthe gate valve 20 are opened simultaneously so as to inject pressurizedwater into a housing 14 accommodating magnetic particles or the like ofa rotary disk 13 to sweep the magnetic particles 21 or the like in thehousing 14 into the carrying pipe 6 and drop the magnetic particles 21or the like to the lower end of the carrying pipe 6. The magneticparticles 21 or the like thereby move along the flow of petroleum or thelike in the steel pipe 4 and reach a conical metal mesh 11 attached tothe carrying pipe 6. The magnetic particles 21 or the like are blockedup by the conical metal mesh 11 and magnetically adhere to an innersurface of the steel pipe 4. The resulting adherent layer graduallygrows downward and reaches a circular mesh plate 8 provided at a tipportion of the carrying pipe 6. The magnetic particles 21 or the likethen fill the inside of the steel pipe 4 and form a mass due to magneticforce, suppressing the outflow of petroleum or natural gas. After that,mortar, concrete 27 or the like is injected from the upper opening 7 ofthe carrying pipe 6 and cured to block the outflow of petroleum ornatural gas.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a vertical cross-sectional view showing a state in which asteel pipe including a carrying pipe therein according to an embodimentof the present invention has been cracked.

FIG. 2 is an enlarged vertical cross-sectional view showing a part ofFIG. 1.

FIG. 3 is a cross-sectional view taken along the line A-A shown in FIG.2.

FIG. 4 is a vertical cross-sectional view showing the initial stage ofcharging magnetic particles into a steel pipe according to an embodimentof the present invention.

FIG. 5 is a vertical cross-sectional view showing the final stage ofcharging magnetic particles into the steel pipe.

FIG. 6 is a vertical cross-sectional view showing a state in which afeeding equipment for feeding magnetic particles or the like has beenattached above a carrying pipe of the present invention.

FIG. 7 is a cross-sectional view taken along the line B-B shown in FIG.6.

FIG. 8 is a plan view of a magnetic particle composite bar used to carryout the present invention.

FIG. 9 is a cross-sectional view taken along the line C-C shown in FIG.8.

FIG. 10 is a vertical cross-sectional view of a steel wirerope-reinforced polyethylene carrying pipe used to carry out the presentinvention.

FIG. 11 is a cross-sectional view taken along the line D-D shown in FIG.10.

DESCRIPTION OF EMBODIMENTS

When damage occurs to a steel pipe 4 for petroleum or natural gas wellthat has been installed in the sea, magnetic particles 21 or the likeare sent deeply into the seafloor through a carrying pipe 6 that hasbeen installed and suspended inside the steel pipe 4. To implement this,the outflow of petroleum or the like coming from a lower portion of thecarrying pipe 6 is blocked by a gate valve 20 provided at a lowerportion of a feeding equipment 12 for feeding magnetic particles or thelike attached to an upper opening 7 of the carrying pipe 6. After that,a switching valve 19 provided at an upper portion of the equipment andthe gate valve 20 are opened simultaneously so as to inject pressurizedwater into a housing 14 accommodating magnetic particles or the like ofa rotary disk 13 to sweep the magnetic particles 21 or the like in thehousing 14 into the carrying pipe 6 and drop the magnetic particles 21or the like to the lower end of the carrying pipe 6. The magneticparticles 21 or the like thereby move along the flow of petroleum or thelike in the steel pipe 4 and reach a conical metal mesh 11 attached tothe carrying pipe 6. The magnetic particles 21 or the like are blockedup by the conical metal mesh 11 and magnetically adhere to an innersurface of the steel pipe 4. The resulting adherent layer graduallygrows downward and reaches a circular mesh plate 8 provided at a tipportion of the carrying pipe 6. The magnetic particles 21 or the likethen fill the inside of the steel pipe 4 and form a mass due to magneticforce, suppressing the outflow of petroleum or natural gas. After that,mortar, concrete 27 or the like is injected from the upper opening 7 ofthe carrying pipe 6 and cured to block the outflow of petroleum ornatural gas.

In order to avoid a situation in which it is difficult to feedindividual magnetic particles due to adhesion of magnetic particles toeach other, a paper-wrapped magnetic particle composite bar 15 iscreated. The magnetic particle composite bar 15 is an elongated bar inwhich non-magnetic clay 22 is present between a plurality of magneticparticles. The magnetic particle composite bar 15 is inserted in thehousing 14 of the feeding equipment 12 for feeding magnetic particles orthe like, and the magnetic particle composite bar 15 is caused to flowinto the carrying pipe 6 by the pressurized water. When the magneticparticle composite bar 15 moves from the bottom of the carrying pipe 6to the steel pipe 4, soluble wrapping paper 23 is dissolved by petroleumor the like, and the magnetic particles 21 are dispersed. The individualmagnetic particles 21 firmly adhere to the inner surface of the steelpipe 4. The magnetic particles are sent in this manner.

As shown in FIG. 6, a non-magnetic receiving frame 16 is provided in thehousing 14 of the feeding equipment 12 for feeding magnetic particles orthe like. Four paper-wrapped magnetic particle composite bars 15 areinserted into the receiving frame 16. The magnetic particle compositebars 15 are elongated bars in which the clay 22 is present between aplurality of magnetic particles. The rotary disk 13 is rotated to movethe magnetic particle composite bars 15 to the position of the carryingpipe 6. When the switching valve 19 and the gate valve 20 are opened,the four magnetic particle composite bars 15 are simultaneously fed bythe pressurized water delivered by a pump or the like to respective foursections of the carrying pipe 6 defined by a partition 31, with thereceiving frame 16 left in place. The rotary disk 13 includes eighthousings 14, and the magnetic particle composite bars 15 loaded inhousings 14 are fed in sequence. Accordingly, a large amount of magneticparticles 21 can be continuously fed to the carrying pipe 6.

When feeding of the magnetic particle composite bars 15 has finished,the switching valve 19 for pressurized water is switched to a secondaryconduit 36, and the gate valve 20 of the housing 14 is closed.Consequently, the pressurized water flows into the carrying pipe 6through the secondary conduit 36. Therefore, the magnetic particlecomposite bars 15 that have been sent previously are smoothly sweptdownward.

As the carrying pipe 6, pipes made of nonmagnetic material can be usedsuch as a polyethylene pipe, a steel wire rope-reinforced polyethylenepipe, an impact resistant vinyl chloride pipe and a stainless steelpipe. It is most appropriate to use a steel wire rope-reinforcedpolyethylene pipe 29 as the carrying pipe 6. As used herein, “steel wirerope-reinforced polyethylene pipe 29” refers to a pipe reinforced with aplurality of flexible steel wire ropes 30 in order to resist breakage ofthe steel pipe 4. The plurality of flexible steel wire ropes 30 arecircumferentially disposed and buried inside the pipe wall and eachextends in the axial direction thereof. There are projections anddepressions in the surface of a steel wire rope 30 and thus the steelwire rope 30 can be firmly adhered to and integrated with polyethyleneresin. A pipe connector 32 for connecting the pipes includes areinforcing metal mesh 33 buried near the outer circumference surfaceand a nichrome wire 34 buried near the inner circumference surface. Thepipe connector 32 is produced by injection molding. An end of the steelwire rope-reinforced polyethylene pipe 29 is inserted into a receptaclein the inner circumference of the pipe connector 32, and electriccurrent is applied to nichrome wire terminals 35 so as to fuse the steelwire rope-reinforced polyethylene pipe 29 and the pipe connector 32. Thefusion can provide sufficient resistance to external tensile force.

The magnetic particles 21 have a size ranging from several to severaltens of millimeters. The shape can be rectangular bar-shaped, roundbar-shaped, plate-shaped or the like. The magnetic particles 21 may bewrapped in clay or soluble paper. Alternatively, the magnetic particles21 may form a longitudinal shape with the clay 22 sandwichedtherebetween, and the resultant is wrapped in the soluble paper 23,thereby forming a bar. Iron particles having a spherical shape, roundbar-shape, cube-shape or the like are used. Powdered iron may be mixedwith pebbles, sand or the like and used. The powdered iron and sand orpebbles may be fed into the carrying pipe 6 from another feeding portother than the magnetic particles feeding equipment 12.

The circular mesh plate 8 has a structure in which it is suspended by ahanger bar 9 made of copper alloy or stainless steel. The conical metalmesh 11 is made of copper alloy or stainless steel. The conical metalmesh 11 is sized such that its outer circumference is contact with theinner circumference of the steel pipe 4. Instead of the conical metalmesh 11, a tea whisk-shaped metal obtained by finely splitting andflaring the top half of a thin-wall cylinder may be used.

INDUSTRIAL APPLICABILITY

This method that uses magnetic particles can be widely used in the eventof an emergency such as the pipe being damaged.

REFERENCE SIGNS LIST

1 Sea Surface

2 Seafloor

3 Seawater

4 Steel Pipe for Petroleum or Natural Gas Well

5 Broken Point in Petroleum Well Steel Pipe

6 Carrying Pipe

7 Upper Opening of Carrying Pipe

8 Circular Mesh Plate

9 Hanger Bar of Circular Mesh Plate

10 Fixing Bolt of Hanger Bar

11 Conical Metal Mesh

12 Feeding Equipment for Feeding Magnetic Particles or the Like

13 Rotary Disk

14 Housing Accommodating Magnetic Particles or the Like of Rotary Disk

15 Magnetic Particle Composite Bar

16 Receiving Frame for Magnetic Particle Composite Bar

17 Axial Face of Rotary Disk

18 Motor for Driving Rotary Disk

19 Switching Valve for Pressurized Water

20 Gate Valve of Housing

21 Magnetic Particles

22 Clay

23 Soluble Wrapping Paper

24 Powdered Iron

25 Sand/Pebbles

26 Steel Balls

27 Mortar or Concrete

28 Base

29 Steel Wire Rope-Reinforced Polyethylene Pipe

30 Reinforcing Steel Wire Rope

31 Partition inside Polyethylene Pipe

32 Reinforced Polyethylene Pipe Connector

33 Reinforcing Metal Mesh

34 Nichrome Wire

35 Nichrome Wire Terminal

36 Secondary Conduit

1. A method for blocking an outflow of petroleum or the like due todamage to a subsea petroleum well steel pipe or the like, the methodcomprising: when a steel pipe for petroleum or natural gas well that hasbeen installed in the sea is damaged, in order to send magneticparticles or the like into the seafloor through an carrying pipe thathas been installed and suspended inside the steel pipe, blocking anoutflow of petroleum or the like coming from a lower portion of thecarrying pipe by a gate valve provided at a lower portion of a feedingequipment for feeding magnetic particles or the like attached to anupper opening of the carrying pipe; after the outflow of petroleum orthe like has been blocked, simultaneously opening a switching valveprovided at an upper portion of the feeding equipment for feedingmagnetic particles or the like and the gate valve, whereby pressurizedwater is injected into a housing accommodating magnetic particles or thelike and provided in a rotary disk 13 to sweep the magnetic particles orthe like in the housing into the carrying pipe and drop the magneticparticles or the like to a lower end of the carrying pipe, and themagnetic particles or the like move along the flow of petroleum or thelike in the steel pipe, reach a conical metal mesh attached to thecarrying pipe, are blocked up by the conical metal mesh and magneticallyadhere to an inner surface of the steel pipe, and a resulting adherentlayer gradually grows downward so that the magnetic particles or thelike reach a circular mesh plate provided at a tip portion of thecarrying pipe, fill inside of the steel pipe and form a mass due tomagnetic force, suppressing the outflow of petroleum or natural gas; andafter the outflow of petroleum or natural gas has been suppressed,injecting mortar, concrete or the like from the upper opening of thecarrying pipe and curing the mortar, concrete or the like.
 2. The methodfor blocking an outflow of petroleum or the like due to damage to asubsea petroleum well steel pipe or the like according to claim 1,comprising: providing a non-magnetic receiving frame including severalcompartments in the housing of the feeding equipment for feedingmagnetic particles or the like, placing the magnetic particles in thecompartments, and causing the magnetic particles in the compartments tosimultaneously flow into sections of the carrying pipe by thepressurized water, the sections being formed by dividing the carryingpipe into the same number as the compartments by a partition.
 3. Themethod for blocking an outflow of petroleum or the like due to damage toa subsea petroleum well steel pipe or the like according to claim 1,comprising: in order to prevent the carrying pipe from breaking at thesame time when the steel pipe is broken, using a steel wirerope-reinforced polyethylene carrying pipe in which a plurality offlexible steel wire ropes are circumferentially disposed and buriedinside a wall of the polyethylene pipe and each extends in an axialdirection thereof, and that is capable of sinking in the sea due toweight of the steel wire ropes, as the carrying pipe.
 4. The method forblocking an outflow of petroleum or the like due to damage to a subseapetroleum well steel pipe or the like according to claim 2, comprising:in order to prevent the carrying pipe from breaking at the same timewhen the steel pipe is broken, using a steel wire rope-reinforcedpolyethylene carrying pipe in which a plurality of flexible steel wireropes are circumferentially disposed and buried inside a wall of thepolyethylene pipe and each extends in an axial direction thereof, andthat is capable of sinking in the sea due to weight of the steel wireropes, as the carrying pipe.